title: Hierarchy of fractional Chern insulators and competing compressible states.
abstract: We study the phase diagram of interacting electrons in a dispersionless Chern band as a function of their filling. We find hierarchy multiplets of incompressible states at fillings ν = 1/3, 2/5, 3/7, 4/9, 5/9, 4/7, 3/5 as well as ν = 1/5, 2/7. These are accounted for by an analogy to Haldane pseudopotentials extracted from an analysis of the two-particle problem. Important distinctions to standard fractional quantum Hall physics are striking: in the absence of particle-hole symmetry in a single band, an interaction-induced single-hole dispersion appears, which perturbs and eventually destabilizes incompressible states as ν increases. For this reason, the nature of the state at ν = 2/3 is hard to pin down, while ν = 5/7, 4/5 do not seem to be incompressible in our system.
authors.affiliation: Institut für Theoretische Physik, Universität Innsbruck, A-6020 Innsbruck, Austria and Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany.
authors.forename: A M
authors.initials: AM
authors.lastname: Läuchli
authors.forename: Zhao
authors.initials: Z
authors.lastname: Liu
authors.forename: E J
authors.initials: EJ
authors.lastname: Bergholtz
authors.forename: R
authors.initials: R
authors.lastname: Moessner